Photoshop won't Align Layers

I am having trouble with PS aligning layers in a PSD file. Clicking any of the alignment buttons does nothing. I had this problem with another cheaper image software that ended up being an issue with memory. I had to keep rebooting to fix the problem. But rebooting does nothing this time.

The computer I am using has 4gb of memory.

Any help would be appreciated.

Thanks,
Shadrach

In Photoshop you normaly have to select two layers two align. First the layer you want to align, then the layer to which the first layer should align to.

Example: Align an object
1. Click object layer.
2. Command(CTRL on win)-click on another layer (e.g. the background layer). Now both layers are selected.
3. Now you should be able to use the align controls.

Hope that helps